1. Field of Invention
This invention is an improved deceleration warning system for motor vehicles, especially motorcycles.
2. Discussion of Prior Art
A deceleration warning signal activated by closing the throttle of a motor vehicle provides an increased margin of safety by alerting following traffic to the fact that a vehicle is beginning to slow down, often well before the application of the brakes illuminate the brake light. Generally, three classes of device have been proposed to perform this function: switches directly connected to the throttle linkage, inertial switches, and switches controlled by intake manifold vacuum.
Switches connected to the throttle linkage would need to close when the throttle is at an idle-speed position in order to be effective in low speed traffic. However, when the vehicle is travelling at high speed, even a partial closing of the throttle can result in considerable deceleration without activating the switch, thereby failing to signal a warning to following traffic.
Inertial switches such as pendulum switches or mercury switches are simple and reliable, but in this application can only work on a level road. Climbing or descending a hill would bias the switch toward an always open or always closed state.
Vacuum switch deceleration indicators are activated by the partial vacuum created in the intake passage or manifold when the throttle valve restricts the air flow into the combustion chamber on the intake stroke of the piston. The resulting pressure differential between the combustion chamber and the crankcase, acting on the piston, produces a retarding force on the engine and the vehicle. This process is commonly referred to as "engine braking".